1. Field of the Disclosure
The present application relates to an organic light emitting display (OLED) device. More particularly, the present application relates to an OLED device adapted to prevent the generation of a thickness deviation and to a manufacturing method thereof.
2. Description of the Related Art
Nowadays, display devices have been rapidly developed with the advancement of information communication. Among the display devices, an OLED device using a self-luminous element does not require a separate backlight unit. In accordance therewith, the OLED device has features of being thinner and lower power consumption compared to the other display devices.
In general, an organic light emitting element used in the OLED device can include an anode electrode, a cathode electrode and an organic emission layer interposed between the two electrodes. Such an organic light emitting element enables generates excitons by recombining holes and electrons from the anode and cathode electrodes into the organic emission layer. Also, the organic light emitting element emits light by the excitons transitioning from an excited state to a stable state.
The organic emission layer has been mainly formed using a vapor deposition method. Recently, an ink-jet printing process is being used to form the organic emission layer on a large-sized substrate.
The ink-jet printing process feeds nozzles along a horizontal direction of sub-pixels and drops a liquefied organic emission material into each of the sub-pixels through the nozzles. However, it is difficult to secure enough nozzles opposite to a single sub-pixel due to the structure of the OLED device. Due to this, if at least one of the nozzles shows an abnormity at the formation of the organic emission layer, thickness deviations of the organic emission layer must be generated.
The thickness deviation of the organic emission layer can cause a stain within a sub-pixel. Moreover, if the organic emission layer is applied to a high definition OLED device, the number of nozzles necessary to form the organic emission layer into each sub-pixel must be reduced more. For this reason, the thickness deviation of the organic emission layer must be very sensitive to an abnormal nozzle.